Bonnett Chess, a chess variant invented by prominent West Orange Chess Club member John Bonnett of Caldwell, NJ, is traditional chess with the same exact rules as traditional chess, with the only difference being that the traditional 8x8 board (64 squares) has one extra file on each side and one extra rank above and below while remaining a perfect square board, thereby creating a 10x10 board (100 squares).
The extra file to the left of the a-file is called the m-file and the extra file to the right of the h-file is called the n-file. The rank below the first rank is called the zeroth rank (or rank-0) and the rank above the eighth rank is called the ninth rank (or rank-9). This makes the corner squares m0, n0, n9 and m9.
So basically you're playing traditional chess with the only difference being that at the outset of play there is a border of empty squares around the traditional (64 squares) Board, such that the zeroth and ninth ranks and the m and n files are unoccupied.
As it turns out, in this chess variant, both White and Black have a total of 40 possible opening move options, twice as many as in standard chess.
